OpenAI's flagship conversational assistant; by 2026 the canonical generalist with multimodal input, memory, and Operator agent mode. The benchmark every other app is measured against.
From Wikipedia
ChatGPT is a generative artificial intelligence chatbot developed by OpenAI. Originally released in November 2022, the product utilizes large language models—specifically generative pre-trained transformers (GPTs)—to generate text, speech, and images in response to user prompts. ChatGPT accelerated the AI boom, an ongoing period marked by rapid investment and public attention toward the field of artificial intelligence (AI). OpenAI operates the service on a freemium model. Users can interact with ChatGPT through text, audio, and image prompts.